This invention relates to the provision of an improvement in an apparatus for coupling fabrics by means of glue.
In the field in which fabrics are worked, at present the working which provides for coupling reciprocally two superimposed fabrics provides for holding the fabrics together by means of an intermediate layer of a glue. The glue which is placed between the two fabrics to be coupled is constituted by a product which, due to the combined actions of heating and pressure, exercised by two cylinders on which the two fabrics are wrapped, is dissolved so as to form the intermediate binding agent.
In particular, the glue is deposited within the miniscule cavities present on the knurled surface of a rotating roller usually called xe2x80x9cmillepuntixe2x80x9d on which one of the two fabrics to be coupled slides so that on the side of this fabric which comes in contact with the roller there are transferred micro-drops of glue which had filled the same cavities, thus forming the layer of glue interposed between the two fabrics. Afterwards, the second fabric is extended on top of the surface of the fabric covered by the micro-drops of glue and still subsequently, by means of the compressor cylinders, coupling occurs by reciprocal glueing of the two superimposed fabrics.
The deposit of the glue on the rotating roller is achieved by means of the so-called xe2x80x9craclaxe2x80x9d device, a device constituted by a suitably inclined blade forming an acute angle with the surface of the same roller so as to form a reservoir constantly filled with the product which is going to fill the cavities of the knurled surface of the same roller, which, in turn, rotating, deposits the product on the surface of the fabric to be treated.
In order to allow the glue which is in the form of very fine granules or as a powder, to be deposited in a regular and homogeneous manner in the interior of the cavities present on the surface of the knurled roller, it is necessary that the mass of glue be warmed in advance to a suitable temperature. At the present state of the art, the mass of glue is warmed by conduction of heat from the warmed rotating roller or by providing the same racla device with a circuit of diathermic oil.
An object of the present invention is to provide a racla device which guarantees a constant and regular distribution of the glue on the rotating knurled roller.
A further object is to provide a racla device in which the entire mass of the glueing product contained in the reservoir is maintained at the correct temperature.
Still another object is to provide a racla device which is maintained in contact with the surface of the rotating roller along the entire length of the roller thus exercising on this surface a regular pressure capable of avoiding automatic aiming incidents and ensuring simultaneously continuous cleanliness by scraping of the same surface, that is operating in a manner that the glue is deposited only in the interior of the cavities of the knurled roller and leaves clear the projections in the knurled roller.